The present invention relates generally to photogrammetry, and more particularly to rotational axis determination utilizing photogrammetric data.
The successful operation of certain rotating devices, such as a flight dual axis drive for positioning antennas, is dependent largely on the ability to maintain proper alignment of the device about its rotational axis. To maintain such alignment, data related to the average axis of rotation must typically be collected. Conventional techniques for determining the average axis of rotation are generally ineffective and inaccurate. Even in the absence of such problems, these techniques rely upon manual operation and repeated readings, and are thus extremely slow. For example, optical instruments, such as multiple theodolites, are typically utilized in conjunction with mirrors to measure the average axis of rotation. A conventional theodolite typically includes a telescope, mounted to be rotatable about vertical and horizontal axis, and horizontal and vertical circular is scales against which the angular position of the telescope can be measured, after it has been aligned on a remote target. Data representing the bearing or azimuthal direction of the target from the theodolite location and elevational angle of the target above or below the horizontal is attained. This technique, however, requires a human observer to both align the telescope on the target and read the azimuthal and elevational data from the circular scales. Since manual operation and repeated readings are required, this technique is extremely slow (typically requiring 4 to 6 weeks), costly and subject to error.
What is needed therefore is an apparatus and method which is accurate and time and cost efficient for determining the average axis of rotation for a rotational device.